Active roll stabilization system

Abstract

An active roll stabilization system of a vehicle having an axle with at least two wheels, wherein the axle is provided with a roll stabilizer that is actuated by means of a hydraulic device. The hydraulic device is actuated and controlled by at least one pressure control valve with a preselected pressure level by a pressure supply device, such as a pump. In order to reduce the costs for producing such an active roll stabilization system, the pressure control valve is pilot-operated by a pressure control pilot valve.

1. Apparatus for active roll stabilization of a vehicle including at least one axle having at least two wheels, which axle is provided with a transverse stabilizer that is operated by a hydraulic device that is subjected to a pre-selected pressure level, said roll stabilization apparatus comprising: at least one pressure limiting valve and a pressure supply source operatively connected with the at least one pressure limiting valve, wherein the pressure limiting valve is pilot-controlled by a pressure limiting pilot valve, and including a two-position direction-switching valve for direction-dependent switching of the hydraulic devices, wherein the two-position direction switching valve is pilot-controlled by a single direction-switching pilot valve. 
   
   
     2. Roll stabilizing apparatus according to  claim 1 , including a total pilot pressure reduction valve connected between the pressure supply source and the pressure limiting pilot valve and parallel to the pressure limiting valve. 
   
   
     3. Roll stabilizing apparatus according to  claim 2 , wherein the total pilot pressure limiting valve is subjected to pressure from a tank from which the pressure supply source is supplied. 
   
   
     4. Roll stabilizing apparatus according to  claim 1 , wherein all of the valves include valve pistons that are guided in a cast valve housing in which passageways are cast for supplying hydraulic medium to and for conducting it away from the respective valves. 
   
   
     5. Roll stabilizing apparatus according to  claim 4 , wherein the valves are connected with each other through the cast passageways. 
   
   
     6. Roll stabilizing apparatus according to  claim 4 , wherein the cast valve housing is of die cast aluminum. 
   
   
     7. Roll stabilizing apparatus according to  claim 1 , wherein actuator elements, control elements, sensor elements, hydraulic elements, and electronics elements for operating and controlling a plurality of valves are combined in one unit. 
   
   
     8. Roll stabilizing apparatus according to  claim 7 , wherein the unit is shielded from the environment by a protective covering. 
   
   
     9. Roll stabilizing apparatus according to  claim 8 , wherein the protective covering is a protective plate. 
   
   
     10. Roll stabilizing apparatus according to  claim 7 , wherein the individual control elements, sensor elements, hydraulic elements, and electronics elements are directly connected with each other electrically. 
   
   
     11. Roll stabilizing apparatus according to  claim 1 , wherein the pressure supply source is a pump. 
   
   
     12. Apparatus for active roll stabilization of a vehicle including at least two axles having at least two wheels, which axles are provided with a respective transverse stabilizer operated by respective hydraulic devices that are subjected to different pressure levels, said roll stabilizing apparatus comprising: a pair of pressure limiting valves and a pressure supply source operatively connected with the pressure limiting valves, wherein the pressure limiting valves associated with respective hydraulic devices are pilot-controlled by at least two pressure limiting pilot valves connected in series, and including a two-position direction-switching valve for direction-dependent switching of the hydraulic devices, wherein the two-position direction switching valve is pilot-controlled by a single direction-switching pilot valve. 
   
   
     13. Roll stabilizing apparatus according to  claim 12 , including a fail-safe valve connected between the direction switching valve and one of the hydraulic devices, wherein the fail-safe valve is pilot-controlled by a fail-safe pilot valve. 
   
   
     14. Roll stabilizing apparatus according to  claim 12 , including a direction switching valve for direction-dependent switching of the hydraulic devices, and a fail-safe valve connected between the direction switching valve and one of the hydraulic devices, wherein the direction switching valve and the fail-safe valve are pilot-controlled by a single on/off pilot valve. 
   
   
     15. Roll stabilizing apparatus according to  claim 14 , wherein the on/off pilot valve has three switching states, wherein in a first state of the on/off pilot valve neither the direction switching valve nor the fail-safe valve is switched on, wherein in a second state of the on/off pilot valve only the fail-safe valve is switched on, and wherein in a third state of the on/off pilot valve both the fail-safe valve and the direction switching valve are switched on. 
   
   
     16. Roll stabilizing apparatus according to  claim 14 , wherein the direction switching valve is a 7/2 directional valve. 
   
   
     17. Roll stabilizing apparatus according to  claim 12 , wherein at least one of the pair of pressure limiting valves and the direction switching valve and the fail-safe valve is subjected to a pressure from a tank from which the pressure supply source is supplied. 
   
   
     18. Roll stabilizing apparatus according to  claim 12 , wherein the pressure supply source is a pump. 
   
   
     19. Roll stabilizing apparatus according to  claim 12 , wherein the direction switching valve is a 7/2 directional valve.